[fedora-virt] F12 and ksm/ksmtuned: info required...

[Kashyap Chamarthy]

On 11/24/2009 08:00 PM, Dan Kenigsberg wrote:
> On Tue, Nov 24, 2009 at 06:43:42PM +0530, kashyap chamarthy wrote:
>> On 11/24/2009 05:31 PM, Gianluca Cecchi wrote:
>>> On Tue, Nov 24, 2009 at 12:50 PM, Dan Kenigsberg<danken at redhat.com>   wrote:
>>>>
>>>> yes, the purpose of ksmtuned is to tune ksm parameters, or stop it
>>>> altogether if it is not needed. In case your two virtual machines
>>>> required less than available memeory, ksm is not used. If ksmtune senses
>>>> that memory stress has risen, it fires up ksm again.
>>>>
>>>> I don't think this is written anywhere but in the code.. We probably
>>>> should add something to the "User experience" section to that feature page.
>>>> How about:
>>>>
>>>> Fedora's kvm comes with 2 services controlling the behavior of ksm. One,
>>>> simply called ksm, is just a nice means to start and stop ksm's kernel
>>>> thread. The other, called ksmtuned, controls the first service and tunes
>>>> its parameters according to the memory stress that is generated by KVM
>>>> virtual machines.
>>>>
>>>
>>> It sounds good; I would only add something like this:
>>>
>>> "In case of need, e.g. in minor load situations, ksmtuned can also
>>> stop ksm service at all.
>>> Later, if ksmtuned senses that memory stress has risen, it will fire
>>> up ksm again."
>>>
>>> So that one knows that to monitor the status of ksm is not a good idea
>>> in general.....
>>> Any log configurable to see/trace ksmtuned decisions (start ksm, stop
>>> ksm, increase pages...)?
>>
>> yes, configuratble log/trace info for ksm/ksmtuned would be useful.
>>
>> I see this for configuration stuff - /etc/ksmtuned.conf
>>
>> /kashyap
>
> You'd have to apply the following patch to /usr/sbin/ksmtuned for it to
> easily log into /var/log/ksmtuned. You'd have to add two lines to
> /etc/ksmtuned.conf for this to actually work.

thanks a lot. will try it.

/kashyap

>
> Regards,
>
> Dan.
>